Within the CHFI v11 curriculum, verifying the integrity of digital evidence is a core responsibility of a forensic investigator. The most reliable method to determine whether a file has been tampered with is by examining its cryptographic hash value . A hash value (such as MD5 or SHA-256) is a fixed-length digital fingerprint generated from the file's contents. Even the smallest change to the file-whether intentional or accidental-will produce a completely different hash value, making hash comparison a definitive method for detecting manipulation.
File system logs (Option A) can help reconstruct timelines by showing access or modification events, but logs can be deleted, altered, or incomplete and do not directly validate file content integrity. Hidden attributes or alternate data streams (Option B) are indicators of possible anti-forensics techniques, yet their presence does not confirm that the primary file data was altered. Access Control Lists (Option C) only describe permission settings and ownership, not whether the file itself was modified.
According to the CHFI v11 objectives under Digital Evidence , Data Acquisition , and Evidence Validation
, investigators must calculate and verify hash values during acquisition and analysis to maintain chain of custody , ensure evidence integrity , and support legal admissibility . This makes hash examination the most appropriate and forensically sound choice in this scenario